Darzens reaction of acyl phosphonates with alpha-bromo ketones: selective synthesis of cis- and trans-epoxyphosphonates.
Acyl phosphonates with alpha-halo ketones in the presence of bases at room temperature afford cis- and trans-epoxyphosphonates in good chemical yields and high selectivities using different bases. The diastereoselectivity of this reaction is easily controlled by changing the base. Changing the base from Cs2CO3 to DBU changed the diastereomeric ratio (trans/cis) from 3/2 to 9/1. Moreover, the treatment of the trans isomer with DBU showed a complete conversion to the corresponding cis isomer.
Demir
Ayhan S
AS
Department of Chemistry, Middle East Technical University, 06531 Ankara, Turkey. asdemir@metu.edu.tr
Emrullahoglu
Mustafa
M
Pirkin
Eser
E
Akca
Nazmiye
N
D000097:Acetonitriles / Q000737:chemistry; D001966:Bromine / Q000737:chemistry*; D004852:Epoxy Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D007659:Ketones / Q000737:chemistry*; D063065:Organophosphonates / Q000737:chemistry*; D013237:Stereoisomerism; D013379:Substrate Specificity
D000097:Acetonitriles; D004852:Epoxy Compounds; D007659:Ketones; D063065:Organophosphonates; D001966:Bromine; C032159:acetonitrile